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  <title>Document</title>
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<body>
  <script>
    // var a
    // function fu() {
    //   a = 10
    //   console.log(a, '内部')
    // }
    // fu()
    // console.log(a, '外部')
    const person = {
      age: 18,
      name: 'pink老师'
    }
    const p = person
    person = 1
    p = null

  </script>
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